Magnetic resonance imaging findings of delayed facial palsy after dental procedures suggest viral reactivation as pathogenesis: a retrospective study.

Abstract

We hypothesize that delayed facial paralysis following dental procedures is also associated with viral reactivation. In this study, the brain magnetic resonance imaging (MRI) findings of patients were analyzed to identify the pathogenesis of facial nerve palsy after dental treatment. We retrospectively reviewed the medical records of patients with unilateral facial nerve palsy and identified those diagnosed with delayed facial nerve palsy within 30days of dental treatment. We assessed the clinical characteristics, electrodiagnostic findings, and imaging findings of these patients and looked for MRI findings that support a viral hypothesis for facial palsy. Among 924 patients with facial palsy, 11 (1.2%) had delayed facial paralysis following dental procedures. Patients developed facial palsy at an average of 3.2days (1-11days) after undergoing a dental procedure. The internal auditory canal MRI revealed abnormal enhancement of affected facial nerve in nine patients. The intensity and pattern of the enhancement were similar to those of Bell's palsy. Facial palsy can develop within the days following dental procedures, and the MRI results suggest that delayed facial palsy after dental treatment is related to viral reactivation-like Bell's palsy.